[Physics Class Notes] on Eye Defects Myopia Pdf for Exam

Myopia or short (near) sightedness is an eye condition where a person is unable to see the objects clearly which are kept far away but have no trouble seeing objects which are kept nearby. A person with myopia would have blurry vision when they would see objects kept far away. Generally, it starts to develop during childhood, and its effect increases gradually or rapidly. Its symptoms vary from person to person. If you squint your eyes often while seeing some object which is kept far away or have headaches frequently, then you might have myopia or short-sightedness. It is advised to visit the eye doctor as soon as possible if you experience any of these symptoms often. Eye strain is another symptom of short-sightedness.

What Causes Myopia?

The causes of myopia are as follows:

1. Myopia occurs when there is the elongation of the eyeball along the axis, and because of it, the cornea and eyeball get affected. Hence, the light rays which are supposed to fall on the surface of the retina, are focusing at the front of it, which results in blurry vision. However, the cause of eyeball elongation is unknown to date.

2. Shortening the focal length of the eye lens is another cause of myopia.

3. The overstretching of ciliary muscles beyond its elastic limit can also cause myopia.

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What is High Myopia?

High myopia is a severe case of myopia where a person has nearsightedness of -5.00 to -6.00 D (Diopters). It generally happens to people who have a family history of having the same eye condition and affects about two per cent of the population. Therefore, it is an inherited genetic condition. A person having high myopia becomes susceptible to having glaucoma (open-angle), cataract (nuclear, cortical, and posterior subcapsular), retinal tears which might lead to retinal detachment and myopic macular degeneration. In order to correct high myopia, a person can opt for laser eye surgery since it is the safest option that can correct up to -10 dioptres.

How to Correct Myopia?

Myopia or short-sightedness can be corrected by wearing corrective glasses or contact lenses. In the case of myopia, a concave lens (curved inwards) is used in corrective glasses that correct myopia when placed in front of a myopic eye. It helps in moving back the image to the retina, where it was originally supposed to be, and results in clear vision. A person who is over 18 years of age can undergo laser eye surgery to correct myopia.

Ways to Prevent Further Progression of Myopia

A person with myopia should avoid reading, writing, or operating phones and tablets for too long. He/She should get sunlight very often at a young age because it will lead to lesser chances of having myopia. People having a lack of vitamin D are more prone to having myopia; hence sunlight is a good source of Vitamin D. Healthy food enriched with vitamin A should be eaten to stop short of delaying myopia progression, and it can also be consumed to maintain a healthy eye in general.

Did You Know?

You have a high chance of having myopia, if both parents have myopia or if even one of them has myopia. You are more likely to develop myopia if you spend a lot of time reading, writing, or operating phones and tablets, which are usually kept near your eyes. Generally, it starts around puberty and proceeds to get worse with time until the eye is fully grown. It can also occur in children who haven’t reached puberty yet.